Labs engineers use a synchrotron to design future computer memory

The experimental group pictured at the synchrotron. (L-R) David Vine, Suhas Kumar, Noraica Davila, David Kilcoyne, Niru Kumari, Ziwen Wang and Xiaopeng Huang.

By Curt Hopkins, Managing Editor, Hewlett Packard Labs

Suhas Kumar, post-doctoral researcher in the Systems Architecture Laboratory at Labs, is the lead author and Principal Investigator on several papers which have appeared in prestigious scientific journals, documenting recent discoveries concerning Memristors. Kumar and co-workers comprised a collaboration among HPE, Stanford University and Lawrence Berkeley National Laboratory, led by HPE Senior Fellow R. Stanley Williams.

The main result documented in Nanoscale is a surprising new Memristor operating mechanism, spatially uniform switching, that had not been directly demonstrated previously. By utilizing an advanced in-operando synchrotron measurement technique developed by the same group, Kumar and co-workers demonstrated that high-performance NbTiO memristors exhibited no conduction channel formation (a frequently detected Memristor operating mechanism), but instead exhibited uniform changes throughout the device.

The result documented in ACS Nano was directly observing a filamentary operating mechanism in HfO Memristors. During information storage in Memristors, the group was able to observe separation of oxygen defects, namely vacancies and interstitials, and their recombination during “erasing” of information, thus confirming long-standing predictions on the atomic-level mechanisms governing Memristor storage.

Specifically, by understanding the filamentary mechanism and certain failure mechanisms (including electrode damage, overheating and irreversible oxygen separation), Kumar and co-workers implemented failure-mitigation designs to improve the lifetime endurance of Memristors nearly a thousandfold, the results of which are under consideration for publication.

“In short,” said Kumar, “using the state-of-the-art DOE synchrotron facility at Lawrence Berkeley National Laboratory combined with our cutting-edge measurement technique, we were able to design significantly better Memristors.” By so doing, they increased the number of applications a Memristor could handle and broadened the technology’s scope significantly.

Other members of this group who contributed to the work included HPE researchers Xiaopeng Huang, Noraica Davila, Niru Kumari, John Paul Strachan, Antonio Torrezan and Emmanuelle Merced; Stanford University Professor Yoshio Nishi and his student Ziwen Wang; and LBNL scientists David Vine and David Kilcoyne.